The miniature killer sends a message to Grissom -- another miniature that foreshadows the death of a woman and her cat. With less than 24 hours to prevent the murder, the CSIs work quickly while Grissom regrets holding up the investigation by going on sabbatical.
The actor who portrays the Worldsend Deliveryman, who appears briefly mid-way through the episode, is not the same Scott Wilson who portrays casino mogul (and Catherine Willows' father) Sam Braun.